1. Field of Invention
The present invention relates to a structure design of a motor, and more particularly to an ultra-thin motor structure capable of effectively thinning the motor and improving power density.
2. Related Art
The advent of the so-called information age is due, in most part, to the proliferation of the mass media and the internet, but the development of the spindle motor, which is most often used in Optical Disk Drives or hard disk drivers to store massive electronic data, also plays a key role.
Nowadays, as compact and lightweight designs have become the mainstream of the market and even the norms of the industry, most electronic products have to be made smaller and smaller to meet consumers' insatiable demand for things slim and small. As a result, the thinning of components in such products is becoming increasingly important. The spindle motor is no exception to this trend. Manufacturers have been making every effort to make it smaller, while at the same time, trying hard to keep, or even increase, its operating performance. As nearly all electronic products are required, either by consideration of user comfort or by a device's need for efficiency and ease of operation, to have stable and smooth running motors, such motors as used in Optical Disk Drives and hard disk drivers all have to meet a very high standard in this respect. As a result, many smooth running micro motors have been developed by industries.
However, development of all these micro motors of the prior art have now reached a bottleneck. Most conventional permanent-magnet motors, for instance, be they brushed or brushless, adopt either a radial air gap or a radial magnetic flux structure. As the motors contain multiple permanent-magnets or a lot of soft magnetic materials, they sometimes produce magnetic cogging that make the motors wobble when the motors are running, generating torque ripples and causing uneven rotation or vibration noises of the motors. In addition, the conventional motor structure is stacked with magnetic conducting material, so that thinning of the motor is obstructed.
Additionally, the winding coil of the conventional motor structure employs copper wires, and produces a flux linkage induction for actuating the motor. However, since the manufacture of copper wire diameters is for the most part already standardized, the diameter cannot be varied arbitrarily according to changes in design. Besides, the quality of copper wires is prone to change and variation depending on environment and processing conditions, causing a decline in conductivity. Once conductivity declines, copper loss is increased, which significantly affects the efficiency of the motor and limits the improvement of the efficiency.
Therefore, the conventional motor structure with the magnetic conducting material has the disadvantages of magnetic cogging, thus the operation is not smooth and thinning of the structure cannot be achieved. Therefore, it is an object for those skilled in the art to develop a motor structure, which can thin the motor and improve efficiency.